1. Technical Field
The present invention relates to an imaging display device and a control method thereof.
2. Related Art
In a so-called mirrorless digital camera, an image of an object can be confirmed by a so-called live view operation in which an image in accordance with an image signal imaged by a charged coupled device (CCD) image sensor, a complementary metal-oxide semiconductor (CMOS) image sensor, or the like is displayed on a liquid crystal panel provided on the housing rear surface, an electronic view finder (hereinafter, referred to as EVF) attached to a housing upper portion, or the like in real time.
However, in this live view, considerable delay is caused from imaging the object by an image sensor to displaying on the view finder or the like. Because of this, it is difficult to allow the camera to follow a moving object. Moreover, if an instruction of imaging of a still image based on the displayed object image is given, a gap is generated between the timing of the displayed object image and the timing of the actually imaged still image. In particular, in a case where the objects move fast, it is difficult to image an intended still image.
Because of this, there is a known technique of shortening delay from imaging by an image sensor to displaying by a display unit such as a view finder or the like.
For example, JP-A-2007-243615 discloses a technique of decreasing delay from outputting a signal output by an image sensor to displaying an image based on the signal by synchronizing a signal regulating a timing of driving the image sensor and a signal regulating a timing of reading an image signal with a certain phase difference.
Meanwhile, in a lens used in an imaging display device, if there is a lens with great lens distortion or chromatic aberration, there is also a lens in which such aberration is small. In addition, in a lens having a zoom function, a zooming rate is changeable. However, there is a case where the extent of lens distortion changes in accordance with the zooming rate. Moreover, there is a case where the extent of chromatic aberration of magnification changes in accordance with the zooming rate. Generally, the greater the extent of the aberration is, the longer is the time required for image processing for correcting the aberration.
However, in the imaging display device described in JP-A-2007-243615, a phase difference from the start of a frame of an image sensor to the start of a frame of a display unit (delay time) is constant. Because of this, in the imaging display device in the related art, since it is needed to determine the phase difference in expectation of the maximum aberration that was assumed, there was a limit in decreasing the delay from outputting the signal by an image sensor to displaying an image based on the signal. In particular, in an imaging display device capable of exchanging a lens as in a so-called single lens reflex camera, since the optical properties of a lens for exchange that will be released in the future are unknown, there is a problem that the phase difference cannot be properly set.